It is all obvious or trivial except…

Nice to confirm it of course

Men who were born after the Black Death were taller than men who lived through the Industrial revolution, a study revealed.
The height of men has fluctuated throughout history, according to scientists who analysed 4,700 skeletons over the last 2,000 years.
They found that men were shorter in the Dark Ages than they were during the Roman occupation.
Other peaks were found after the Norman Conquest in the 11th century and between the 1400s and the early 1650s.

Richer times mean children are better nourished. This shows up as their being taller – but also as more surviving to have children. Population increases and per capita living standards decline to subsistence once again. At which point adults are shorter again.

Jonathan – most of the roman soldiers were from an agrarian society too. You could look at race though – were northern Europeans taller than the southern Europeans? Not Ynys Prydain versus Rome but the wider groups.